Why is it so hard to swat a fly?
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1) Eyes don't work like cameras; there's no real "exposure" phase as such (even though there's lots of thresholds). So it's misleading to talk about discrete images that we sample at some fixed frequency. Instead, it's much more helpful to think of photoreceptors and subsequent processing stages as continuous band-pass filters. At some point, high frequencies are simply cut off because the electro-chemistry of the cell can't keep up. For us, that cut-off comes earlier than it does for invertebrates.
2) There's no mechanical interaction between light and photoreceptor. Instead, the transduction cascade of the dipteran eye seems to encompass a mechanical (as opposed to biochemical) step.
3) It's pure conjecture to talk about a fly's slowed down "perception" of the world. The reason why they take off before you get to them is much simpler -- there's a highly optimized reflex that connects eye and flight muscles via the giant fiber (a particularly rapid nerve). We have similar responses, like eye lid closing etc. Additionally, their photoreceptors are sensitive and fast. But there's zero evidence that flies have any sense of continuous time that could be faster than ours.
Ah, well. The perils of science journalism.
They might not view time faster, but they view and react to events much closer to the present.
A maybe-dumb question about point (3) - I've noticed that when I get a blink/flinch response from something (usually some sand or a bug hitting my face when I'm on the bike), it feels like I blink just a split second before the thing hit me. Given that I'm unlikely to have any kind of precognition, do you think this might be related to the blink reflex being 'hard wired' and so my brain gets the "hey, a thing hit your face" signal after the "hey, your eyes just closed" signal? (Alternately, I read something once about our perception of audio being delayed by ~100ms so that it synchs up with our perception of vision, despite our visual processing being slower than audio - maybe the signal that caused the flinch gets 'buffered'?)
We know very little about conscious perception or even the locus at which sensory signals are integrated to generate a conscious percept. But it's perfectly possible that delays differ across modalities and that the proprioceptive signal about lid-closing reaches whatever-relevant-area before your visual system catches up.
> I read something once about our perception of audio being > delayed by ~100ms so that it synchs up with our perception > of vision
Not an expert on audition, but the brain is really good at generating coherent representations of the physical world across modalities. I wouldn't be surprised if such cross-sensory synchronisation happened in some form.
If such a delay does occur it is considerably less than 100ml as that kind of latency would be very noticeable playing a musical instrument.
See: https://www.nature.com/neuro/journal/v17/n7/full/nn.3741.htm...
Short abstract snippet (the "parallel circuits" are other, non-giant descending neurons that also trigger the escape behavior upon a looming stimulus):
"Intracellular recording of the descending giant fiber (GF) interneuron during head-fixed escape revealed that GF spike timing relative to parallel circuits for escape actions determined which of the two behavioral responses was elicited. The process was well described by a simple model in which the GF circuit has a higher activation threshold than the parallel circuits, but can override ongoing behavior to force a short takeoff. Our findings suggest a neural mechanism for action selection in which relative activation timing of parallel circuits creates the appropriate motor output."
Aim for a spot about 1-2" behind the fly, and about 1-2" above the fly. Try to catch it there, and your success percentage will be high.
2) see the fly walk over your food, your face, your kids food...
Do you want to touch a "dirty" fly, or eat what the fly has walked on?
I'll take #1 any day.
Seriously, we have become irrational animals afraid of everything. (I would wash my hand after splashing a fly if there was a rotten corpse around, though, and would have done even without the fly because my nose would have alerted me of a chemical danger.)
an easy way to catch flies is to put rubbing alcohol in a squirt gun. even less than direct hits takes them out of the sky, and the alcohol cleans stuff in collateral damage.
Yes, I have a lot of time on my hands.
Also a lot of fly goo.
The spray is likely to hit it. Wet flies don't.
Mostly because they make an awesome sound.
Also, the greatly reduced drag and holes in the surface give fewer warnings to the fly that it's about to be hit, while the use of a tool allows for faster hits. It's really a pretty great invention to kill a lot of flying insects.
When swatting, I've found they can only fly forward and had good success anticipating that movement. Apparently others in this thread can catch them on the fly's initial backwards jump, which I had never noticed.
And some more references on how compount eyes see mechanically, as opposed to chemically, would be interesting.
Spray at it with any liquid (e.g. water, household cleaner). It may take a couple of squirts but it's easy as it doesn't need to be exact. The fly will fall to the ground where you can just squash it with a tissue.
Every once in a while we get a number of flies in the house during the summer when the doors and windows are open. They tend to gather in the sides of our windows, looking for a way out. I used to catch them one by one, and then I tried a vacuum. It was easy, once they are aware of the vacuum it's too late to fly away, and they get sucked right up. It's probably not worth while for one or two flies, but if you're going after a few a vacuum can be really effective.
I’ll never forget seeing Mike catch that fly.
It doesn't mean that they only see moving objects by the way. In flight they see because everything is moving around them.
Other techniques I've employed: (1) cling film (saran wrap), (2) detergent spray (slows em down; dispatch after 2-4 rounds), (3) vacuum cleaner nozzle (they hunker down but are sucked in upon take-off)